1. Field of the Invention
The present invention relates to a navigation apparatus and a computer program product for navigation control.
2. Description of the Related Art
There are car navigation apparatuses known in the related art that are equipped with functions for displaying a roadmap around the current vehicle position, for determining through an arithmetic operation a recommended route from the start point to the destination, for providing route guidance based upon the recommended route determined through the arithmetic operation and the like.
Such a car navigation apparatus displays the recommended route and the like on a roadmap displayed at a monitor. This allows the user to ascertain the current vehicle position and the recommended route in relation to the roadmap, affording great convenience.
However, there is a problem in that a huge volume of data must be handled and a great deal of time is required for the processing in order to display the roadmap. As a result, the car navigation apparatus requires a large storage capacity, a high-speed CPU and a high-performance display device, which leads to higher costs.
The present invention provides a low-cost navigation apparatus and a computer program product for navigation control that may be used to realize the low-cost navigation apparatus.
The navigation apparatus according to the present invention comprises: a current position detection device that detects a current position; a display device; a storage device having stored therein position information related to points used as guidance points when providing route guidance; and a control device that controls the route guidance provided along a guided route which includes a plurality of predetermined guidance points based upon the current position detected by the position detection device and the position information related to the points stored in the storage device, wherein: as the current position approaches a first guidance point closest to the current position, the control device engages the display device to bring up display of an arrow indicating an angle corresponding to a direction to follow to advance toward a second guidance point after the first guidance point.
In the navigation apparatus, it is preferred that the control device determines the direction to travel to advance toward the second guidance point through an arithmetic operation executed in reference to the first guidance point.
In the navigation apparatus, it is preferred that the control device determines the direction to travel to advance toward the second guidance point through an arithmetic operation executed in reference to the current position.
In the navigation apparatus, it is preferred that the control device does not display a roadmap at the display device.
In the navigation apparatus, it is preferred that the control device displays a straight arrow at the display device while the current position is still distanced from the next guidance point.
In the navigation apparatus, it is preferred that the control device displays the arrow as a bent arrow and if another road intersects the guided route between the current position and the first guidance point, the control device brings up a supplementary indicator on display corresponding to the intersecting road between an arrow tail and a bending point.
A computer-readable computer program product according to the present invention contains a navigation control program, with the navigation control program comprising: a current position detection instruction code for detecting a current position; a position information acquisition instruction code for obtaining position information related to points used as guidance points in route guidance; and a route guidance control instruction code for controlling the route guidance provided along a guided route that contains a plurality of predetermined guidance points based upon the current position detected in conformance to the current position detection instruction code and the position information related to the points obtained in conformance to the position information acquisition instruction code, wherein: in conformance to the route guidance control instruction code, control is implemented so that as the current position approaches the first guidance point closest to the current position, an arrow indicating an angle corresponding to a direction to travel to advance toward a second guidance point after the first guidance point is displayed at a display device.
In the computer program product, it is preferred that in conformance to the route guidance control instruction code in the navigation control program, control is implemented so as not to display a roadmap at the display device.
It is preferred that the computer program product is a recording medium having recorded therein the navigation control program or a carrier wave having the navigation control program embodied as a data signal therein.
FIG. 1 is a block diagram of the car navigation apparatus according to a first embodiment;
FIG. 2 shows a schematic map provided to facilitate an explanation of the arrow navigation;
FIGS. 3A-3D present examples of arrows that may be used in the arrow navigation;
FIG. 4 presents a flowchart of the basic control of the arrow navigation executed at the arithmetic processing unit;
FIGS. 5A and 5B illustrate how the arrow navigation is executed in a second embodiment;
FIG. 6 illustrates the concept of the arrow navigation adopted in a third embodiment;
FIG. 7 presents a flowchart of the basic control of the arrow navigation executed at the arithmetic processing unit in the third embodiment; and
FIG. 8 shows how the program may be provided via a transmission medium.